This invention relates generally to a door fitting device for those doors which are rotatingly opened and closed with a perpendicular axis being the center. More particularly, the present invention relates to a door fitting device of the type in which a door closing rotary torque is provided by a torsion bar which undergoes elastic deformation.
In a door which rotates with a perpendicular axis being the center for the opening and closing operation, only one side of the door is supported by a fixed frame of the main body of a door by the door fitting device. Therefore, the weight of the door acts as an eccentric load upon the door fitting device and the door is likely to be inclined to its other unsupported side. When the other side of the door inclines downward beyond an allowable limit in the course of repeated use for an extended period of time, the door will not operate because the lower end of the unsupported side strikes a lower fixed frame. Therefore, the axis of rotation must be moved and adjusted in such a direction as to absorb the inclination of the door.
In order to use the door fitting device for a variety of doors having varying weights, the twist deformation quantity of a torsion bar under the door closed state, that is, an initial set quantity of the rotary torque, must be adjustable and changeable.
As an example of apparatuses which can relatively easily change and adjust the axis of rotation and the setting of the initial rotary torque, mention can be made of the door fitting device disclosed in Japanese Patent Laid-Open No. 191878/1983.
The door fitting device described above adjusts the setting of the initial rotary torque by the use of a worm wheel and a worm. Since a recess for storing the worm wheel is formed on the lower surface of a movable case, it is necessary to first store the worm wheel in the recess and then to fix a cover plate abutting on the lower surface of the worm wheel to the movable case in order to prevent the fall of the worm wheel.
At the stage of coupling and connecting the torsion bar to the worm wheel, it is by no means easy to fit a non-circular lower end portion of the torsion bar into a non-circular opening at the center of the worm wheel because the worm wheel is already assembled in the movable case and is disposed at the depth of the recess of the case.